Checker structure



June 20, 1950 J. J. SEAVER CHECKER STRUCTURE 3 Sheets- 1 Filed April 3 1947 FIG. 3

ENTO BY M MKQ June 20, 1950 J. J. SEAVER 2,512,555

CHECKER STRUCTURE Filed April 3, 1947 I5 Sheets-Sheet 2 JAY 55/11 52 INVENTOR.

BY M

A TTYS.

5 Sheets-Sheet 5 INVENTOR.

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\JP\Y d. SEAVER.

J. J. SEAVER CHECKER STRUCTURE June 20, 1950 Filed April 5, 1947 Patented June 20, 1950 UNITED STATES PATENT OFFICE Claims.

For various industrial uses, as in' blast furnaces and open hearth furnaces, it is desirable to supply heated air to a furnace so that the resulting temperature would be higher than it would be with colder air.

The most common and efficient method of heating the air is to run it through a checker chamber which has previously been heated by running hot products of combustion therethrough. In the case of the open hearth furnace, the products of combustion from the furnace are passed through a checker chamber to heat it while air for the combustion is drawn through another checker chamber previously heated. After a certain interval of time, 'the process is reversed so that air for combustion is drawn through the freshly heated checker chamber and the other checker chamber is heated by the products of combustion from the furnace.

In the case of blast furnaces, a plurality of stoves are provided, each having its special com- I bustion chamber for producing the hot gases which heat up the checker chamber. After a suitable heating interval, the local combustion given total cubic volume, and with adequate'open cross section for the flow of gas, more exposed surface area can be provided, it is obvious that the heat transfer will be greater first from the The efi'iciency of the invention permits the building of a checker work in which there is communication between ducts even though the brick is of a shape economically manufactured. Furthermore, the communication between ducts is so good that if a stoppage occurs in one duct, substantially the entire duct except where the stoppage occurs can be fully utilized.

The same shape which provides the abovementioned advantages lends itself also to a costless provision for interlocking of the bricks. Interlocking has long been recognized as desirable. Complicated and'expensive shapes of bricks have been proposed to provide interlocking. Without interlocking, there is occasionally trouble due to separation of sections of the brick under the infiuence of repeated expansion and contraction, and sometimes vibration. Excessive movement of the bricks can even cause some of them to lose their support, with the result that a, section of the checker work may partially collapse. The tapered upper ends of the bricks leave room for exhaust gas to the brick and then from the brick shape which is not subject to the former objections of greatly increasing the cost of manufacture.

In the past, a, checker work structure has been proposed which provided some communication between the longitudinal air ducts therethrough.

downwardly projecting lugs on upper bricks. Such lugs may be formed by extrusion and according to the preferred form of the invention these lugs are therefore provided. They are arranged to keep each brick centered under the one cross-wise above it and to limit its movement with respect to other bricks. This interlocking feature could be provided without tapering the upper ends of the bricks, merely notching them to receive the lugs. Such construction is, therefore, within this phase of the invention even though the tapering of the upper end for the advantages discussed in the preceding paragraph is greatly preferred.

The present application is in part a continuation of applications Serial No. 481,242 and Serial No. 530,672, filed, respectively, March 31, 1943, and April 12, 1944, both abandoned prior to the issuance of this patent.

Additional objects and advantages of theinvention will be apparent from the following dethe showing several courses of the brick, one course being partially broken away to the line 3-3A of Fig. 2;

Fig. 4 is a vertical, sectional view taken through a stove embodying the checker work of this invention;

Fig. 5 is a horizontal, sectional view taken approximately on the line 5-5 of Fig. 4;

Fig. 6 is a face view of one form of brick;

Fig. 7 is a face view of another form of brick;

Fig. 8 is a view corresponding to Fig. 1 but showing bricks provided with the interlocking lugs, except on the bottom level;

Fig. 9 is a view corresponding approximately to Fig. 3 but showing the interlocking lugs;

Figs. 10 and 11 are side and end views respec tively of a modified form of the interlocking brick in which the tapered portions are provided with a transverse double taper; and

Fig. 12 is a face view of a, brick embodying the interlocking features without the other features of the invention.

Although the law requires a full and exact description of at least one form of the invention, such as that which follows, it is, of course, the purpose of a patent to cover each new inventive concept therein no matter how it may later be disguised by variations in form or additions of furtherimprovements; and the appended claims are intended to accomplish this purpose by particularly pointing out the parts, improvements, or combinations in which the inventive concepts are found.

One type of'structure in which the invention may be used is illustrated in Figs. 4 and 5. The structure here illustratedis a hot blast stove for heating the air for a blast furnace, during the heating period, while air is being supplied to the blast furnace from some other stove. The stove includes a combustion chamber H and a checker chamber [2 both of which are suitably insulated externally as in the prior art. At the bottom of the combustion chamber II is located a gas burner 14 through which fuel and air are supplied to burn in the combustion chamber and to pass downwardly through the checker chamber l2, anclout through one or more chimney valves l5 to a chimney. When the bricks in the checker chamber 12 havbeen heated to the desired extent, the burner 14 is closed, the chimney valves l-fiyare closed, and cold air is admitted through cold blastvalve I8. This air passes upwardly through the checker chamber 52 and down through the combustion chamber to hot blast valve through which the-heated air passes to the blast furnaces.

Checker work The checker work may be supported in any suitable manner, one conventional method being to support it on grill work 22 which is in turn supported by means 24. In the first course of brick, some of the checker .bricks .28 lie along grill bars 22 while others bridge between them.

The preferred arrangement is that illustrated and approximately the shape shown. Of course, the dimensions may be varied as desired. One suitable size, however, is eight inches long, seven and one-half inches high, and two inches thick. The dimensions of the omitted triangular portion indicated at 32 in Fig. 6 may desirably be four and three-quarters inches high by two inches wide at the top. With the arrangement illustrated in Fig. 1, this will provide vertical fines three inches square.

An important feature of this invention is that the vertical fiues are interconnected at frequent intervals. In fact, at each course of bricks, each flue will be cross-connected to each of the four lines immediately surrounding it. Thus, if we assume that a stoppage for some reason occurs at apoint 34 in one flue, all of the length of this flue, except in the course involved in the stoppage will, nevertheless, be used, for the gases will flow considerably increased. The portions of the brick which are in contact with one another are not available for heattransfer between the air and brick. ,Omitting the corners of the bricks decreases the total'jsu'rface area of the brick, but iu cre'asesv the exposed surface area so that each brick is considerably more efiicient as a heat transfer medium than heretofore. Furthermore, thepercentage of the volume of the brick within one inch of anexposed surface is increased so that the brick is more completely heated and cooled.

At each point where the corner of a brick is omitted, the flow area of the duct is increased. Hence, the gases tend to expand into this increased flow area and reduce their velocity and ccntract therefrom and increase their velocity at each point.

. omitted corners will tend to clean away any incipient stoppage so that relatively few stoppages willoccur.

The thermal efiiciency of the checker work is still further increased by providing each brick with a'hole M, as seen at the right hand side of Figs. 1 and 3 and as shown'in Fig. 7. This hole .prevides a considerable increase in the amount of areaof the brick which is exposed. It is-especially helpful in heating the portion of the brick which v is directly below the hole and which otherwise would not be within an inch of any exposed surface. However, it also speeds the heating ofthe nels.- Beyond all this, however, the hole is helpful in increasing the circulation between channels andthe flow of gases in contact with the sloping edges o he rick where the cor er 32 a emitted s that t qwe a t o ieareais Although Figs. 1 and 3 have shown some bricks with'thehole 4| therein and some without, and while both could be used in the same checker 3 structure, it is probable that ordinarily only one .or the other would be used.

.- As seen in Figs. 8 and 9, the spaces left by the omittedcorners (the spaces 32 in Fig. 5) maybe used for receiving interlocking lugs 5| provided -,.on the bottoms of the bricks. The two lugs 5| are v s gaaced apart so as to receive the top of a transversely disposed brick therebetween and they are, ,spaced from the. corners so as to receive the upper corners of underlying parallelbricks. This interlocking is clearly shown in Figs. 8 and 9.

. Figure 12 shows a brick provided with these in- Figs. and 1 1 illustrate a construction similar to.that of Figs. .8 and 9 except that the converging portions of the brick are provided with faces which slope from an intermediate ridge .56 downwardly to the main front and rear faces of the brick. portions of the brick are provided with a transverse. double bevel. This tends to prevent any In other words, the converging soot or other solid particles from coming to rest I on the brick and perhaps filling up the corners which were omitted for giving the advantages previously discussed. Although applicant had privately suggested this feature of the construction long ago, it was believed to represent sub- .stantial added cost and is not believed to be necessary. To the extent that it is advantageous,

there are many shapes whichwill serve its purpose- All that is necessary is that in thevicinity; of the bottom of the converging end faces there be a sufiicient slope toward the main front and back faces (preferably as steep as the angle .of slide between bricks and soot) to shed solid 2 particles under conditions encountered. 1 illustrated shape, gives less volume reduction, a

The

factor in brick prices. The hole 4| is shown higher in this form of brick than in Fig. 8 so as to clear the ridges 56 of adjacent bricks.

It will be observed that in spite of having the a various advantages discussed, the brick, even the form of ,Figs. 10 and 11, is of an exceedingly simple shape. ,Its manufacture need not be any more difficult or expensive than that of ordinary bricks and, to the extent that the omitted corn'ers represent a saving of material, it may be less expensive. wise formed in bars having a cross-section corresponding to the shape of the face of the fin- ..ished brick and the individual bricks may be 1 sliced from this bar.

pressed to make their dimensions accurate in- The clay may be extruded or other- Of course, they can be reasmuch as they are laid without mortar. However, it is believed that repressing will not prove any more necessary than if th features of this -.invention were omitted. The beveled portions where the corners are omittedneed not be abi-solute1yaccurate and, therefore, have no special need to be repressed. Repressing is now so comm0 n that-even the simple ridge 56 repre- ,sents no .extra cost- In fact, if repressing is practiced, the hole 4| furnishes new space for any excess material. The .bar from whichv the bricks are sliced may be extruded with thehole 4| in'it so that the hole in the brick does not represent an added cost. i

It may be noted that although the bricks of this invention have been shown resting di- .rectly on the grill bars 22, it will probably be more economical to use narrowergrillbars and interpose between them and the illustrated brick a course. of three-inch brick or. tile, the illustrated brick restingon themin the same manner in which they have been illustrated as resting on the grill bars 22.

The stove shown in Figs. 4 and 5 may be conventional except for the checker work. Its main walls are, of course, refractory.

Although the brick has been shown in its preferred position with its small side up (when only part of the benefits are desired), it could be used upside down or sideways, and, of course, its shape could be considerably varied and still use at least some aspects of the invention.

From the foregoing, it is seen that a new checker work and a new brick therefor have been invented which, with-out any increase in cost, provide a checker work which is more efficient and in various ways more satisfactory than those heretofore known, especially as compared with any of the simpler and less expensive brick shapes of the past. The checker work may, of

course, be used for a variety of purposes.

The preferred form of brick has a higher percentage .of clayclose to an exposed surface and provides cross-flow between flues; Also, each brick interlocks with other brick to prevent gradual twisting and other displacements, sometimes occurring heretofore, chiefly onaccountof expansion and contraction due to. frequent changes of temperatures;

1. A checker brick formed ofrefractory material of a thickness much less than itslength and height and reduced symmetrically. about a center line in one of its major dimensions along a part of its other major dimension, said brick having a hole therethrough on said center line and extending in a direction of its minor dimension and positioned below the top of the portion of the brick on the center line so that the hole will be exposed adjacentthe reduced portion of a like brick assembled with its end. facing the hole and the bottoms of thebricks at. the same level.

2. A regenerator checker work comprising successive courses of brick arranged in basket weave pattern with the bricks of one course staggered with respect to the bricks of the next but providing continuous and approximately straight flues therethrough, the wallsof .the fiues being formed by the faces of the bricks, each brick having its ends converging upwardly to viding'. continuous. andapproxi-mately straight ,flues. therethrough, the walls. ofthe flues being formedabythe faces of the bricks, eachl-brick having .its. ends converging upwardly to form interconnections between thefiues and to increase the total exposed area of the bricks, eachbrick spanning three bricks belowit with its lower cor- .ners approximately resting on bricks parallel thereto, the center portion of itsbottomapproxi- .mately resting on a bricktransvers thereto, and intermediate portions lying over the spaces vformedby the converging ends'o'f the parallel said faces and generally flat to form a supporting surface, and having its ends converging upwardly symmetrically about a, center line, said brick having ahole from face to face on said centercline and positioned below the top of the portion of the brick on the center line with at leastrpart of the hole as high as the bottoms of the. converging end walls.

; A- checker. brick formed of refractory material and shaped with a, thickness much less. than its len-gth and height, having two generally flat faces,- having abottom face perpendicular to said facesand generally flat to form a supporting surface, and having its ends converging upwardly symmetrically about a center .line, said brick having .a hole from face to face on said center line,.and positioned with at least part of the hole as. high as the bottoms of the converging end walls; and the top of the brick being generally flat continuous across the said center line.

6. A checker brick formed of refractory-material and shaped with a, thickness much less than its length and height, having two generally fiat faces, having a bottom face perpendicularto said faces and generally fiat to form a supporting surface; and having its ends con-verging upwardly symmetrically about a center line, said brick having a hole from face to face on said center line-and positioned belowthe top of the portion of the brick on the center line but with at least part of the hole as high as thebottoms of the converging end walls, and the top of the brick being generally flat continuous across th said centerline for a distance wider than the thickness of the brick.

7. A checker brick formed of refractory mate rial and of a thickness much less than its length and its height, having generally fiat and parallel front and rear faces and having upwardly converging faces disposed along at least the upper portions of the ends of the brick and havingits bottom face provided with interlocking lugs spaced apartto receive a transversely disposed brick between them and spaced from the lower edgesof thebrick ends to receive the upper corners of correspondingly shaped bricks, the space formed by the upwardly converging faceof the bricks being shaped to receive the lug ofan upper brick which is placed in parallel relationto said brick.- I

8. A-regenerator checkerwork comprising successive courses of brick arrangedin basket weave pattern with the bricks ofo'ne course staggered with respect to the bricks of the next prov iding con-tim-ious and approxi-matelystra-ight 'fliics" thcfthroirgh; the walls of the" fiues being formed-b the faces of the bricks, each brick having itsend's converging upwardly to form interconnections between the fines and to increase the total exposed area of the bricks, and each brick spanning three bricksbelow it with its lower corners approximately restingon bricks parallel thereto, the center portion of its bottom approximately resting on abrick transverse thereto, and intermediate portions extending partial-1y intothe spaces formed by the converging ends of the parallel bricks to interlock with the three supporting bricks;

9. A regeneratorchecker workcomprising success'ive courses of brick arranged in basket weave pattern with the bricksof one course staggered with respect to the bricks of the next but providing continuous and approximately straight flues therethrough, the walls of the flues being formed by the faces of the bricks, each brick having its'ends converging upwardly to form interconnections between the fines and to-in'crease the total exposed'area of the bricks, and eachbri'ck spanning three bricks below it with its lower corners approximately resting on bricks parallel thereto, the center portion of its bottom approximately resting on a brick transverse thereto, and intermediate portions extending partially into spaces formed bythe parallel bricks to interlock with the three supporting bricks.

10. A regenerator checker work com-prising successive courses of brick arranged in basket weave pattern with the bricks of one course staggered with respectto the bricks of the next but providing continuous and approximately straight cues therethrough, the walls of the flues being intermediate portions extending partially into spaces formed by the parallel bricks to interlock with the three supporting bricks.

11. A checker brick formed of refractory niaterial and of a thickness muchless than its length and its height, havinggenerally fiat front and rearfaces and having upwardly converging faces along at least the upper portions of the ends 'of the brick and having its bottom face provided with interlocking lugs spaced apart toreceive a transversely disposed brickbetween themand spacedfrom the lower edges of the brick-encl'sto receive the upper corners of correspondingly shaped bricks, the space formed by theupwardly converging face of the brick being shaped to receivethe lug of an upper brick which is placed in parallel relation to said brick.

12. A checker brick'formed of refractory material of a thicknessmuch less than its; length and height. and of a shape suitable. for basket eave arrangement including substantially flat front and back faces, said brick having lugs-extending downwardly from the bottomportion equally distant from the center thereof and spaced apart approximately the thickness of the brick to interlock with a similar brick on which the brick rests and to hold the bricksapproximatelyperp'endicular to one another; the upper portions of the brick having depressions therein toreceive the lugs of bricks parallel with the brickand resting" thereon.

l3. A refractory basket-weave type checker brick of a thickness much less than itslength and height, having'generally flat'fro'nt and rear races disposed perpendicularly to bdttoifi race and a top race, and having a bearing surface at each end of such bottom face level with a bearing surface at the center of the bottom face, which center bearing surface extends lengthwise of the brick for a distance at least equal to the thickness of the brick, such top face having a central bearing surface of a length which is less than the over-all length of the brick but which is greater than the thickness of the brick, and said brick having ends converging upwardly toward the top to form recesses which each extend both lengthwise of the brick and vertically a distance equal to at least the thickness of the brick.

14. A refractory basket-weave type checker brick of a thickness much less than its length and height, having generally fiat front and rear faces disposed perpendicularly to a bottom face and a top face, and having a bearing surface at each end of such bottom face level with a bearing surface at the center of the bottom face, which center bearing surface extends lengthwise of the brick for a distance at least equal to the thickness of the brick, such top face having a bearing surface of a length which is less than the overall length of the brick but which is greater than the thickness of the brick and being flanked by recesses which each extend both lengthwise of the brick and vertically a distance equal to at least the thickness of the brick; said brick having a hole therethrough midway between its ends 39 and extending higher than the end faces below the recesses.

15. A refractory basket-weave type checker 10 brick of a thickness much less than its length and height, having generally fiat front and rear faces disposed perpendicularly to a bottom face and a top face, and having bearing surface at each end of such bottom, face level with a bearing surface at the center of the bottom face, which center bearing surface extends lengthwise of the brick for a distance at least equal to the thickness of the brick, such top face having a bearing surface of a length which is less than the over-all length of the brick but which is greater than the thickness of the brick and being flanked by recesses which each extend both lengthwise of the brick and vertically a distance equal to at least the thickness of the brick; said brick hav- REFERENCES CITED The follOWing references are of record in th file of this patent:

UNITED STATES PATENTS Number Name Date 1,980,827 Reed Nov. 13, 1934 2,303,741 Hiller et a1. Dec. 1, 1942 2,412,552 Aflleck Dec. 17, 1946 

